> If there is no way to obtain what I want, is it possible to write my own
> function in Maxima to do it?
Try with
gnuplot_curves(l) := block(
[numer:true, display2d:false],
with_stdout("maxout.gnuplot",
print("set zeroaxis"),
print("plot '-' with lines 1"),
for x in l do
print(x[1], x[2])
),
system("gnuplot -persist maxout.gnuplot")
)$
Andrej